title: The effects of pneumoperitoneum on gastric blood flow and traditional hemodynamic measurements.
abstract: BACKGROUND
  The purpose of this study was to investigate the effects of increasing intraabdominal pressure (IP) on gastric blood flow, as measured by gastric tonometry and traditional hemodynamic measurements.
  
  
  METHODS
  Nine swine were anesthetized, intubated, and ventilated. Arterial and pulmonary artery catheters were placed by cutdown, a trocar was placed in the abdomen, and a gastric tonometer was placed in the stomach. Serial measurements of arterial and mixed venous blood gases, cardiac output, wedge pressure, lactic acid, and gastric intramucosal pH (pHi) were collected at intraperitoneal pressures of 0, 8, 10, 12, 14, 16, and 18 mm Hg after 30 min equilibration. Statistical analysis included Pearson correlation and Student's t test.
  
  
  RESULTS
  Increasing levels of IP were correlated with decreased arterial pH (p < 0.00003), increased mixed venous CO2 (p < 0.003), decreased intramucosal pH (p < 0.014), and increased arterial CO2 (p < 0.015). Gastric pHi differed significantly from baseline at IP levels of 16 mm Hg (p < 0.004) and 18 mm Hg (p < 0.01). No significant effects were observed on cardiac output or arterial lactate. No significant effects were observed in a control group that had been insufflated to 8 mm Hg and held constant over 3 h.
  
  
  CONCLUSIONS
  In this model, gastric blood flow is adversely affected by increasing i.p. with pronounced effects in excess of 15 mm Hg. These results suggest that gastric tonometry may be used to monitor the adverse effects of pneumoperitoneum. Gastric pHi may be an earlier indicator of altered hemodynamic function during laparoscopy than traditional measures.
authors.affiliation: Department of Surgery, David Grant Medical Center, Travis AFB, CA 94535, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Knolmayer
authors.forename: M W
authors.initials: MW
authors.lastname: Bowyer
authors.forename: J C
authors.initials: JC
authors.lastname: Egan
authors.forename: H J
authors.initials: HJ
authors.lastname: Asbun
mesh_terms: D000005:Abdomen / Q000503:physiopathology*; D000818:Animals; D001784:Blood Gas Analysis; D002245:Carbon Dioxide; D005753:Gastric Mucosa / Q000098:blood supply*; D006439:Hemodynamics / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D010535:Laparoscopy; D008365:Manometry; D011028:Pneumoperitoneum, Artificial; D011312:Pressure; D013552:Swine
chemical_list: D002245:Carbon Dioxide; D019344:Lactic Acid